Need help , Car runing bad.

[BmwEvoSport]

Ok so i just did a Compression test and it came out to 165psi across the board. Now i did notice that Cylinder 2 and 4 are not working . I did this by running the car and pulling one plug wire out at a time to see if the idle changes and it did on all exept for 2 and 4. What els should i check and what do you thing it may be. ???????/// thanks.

[dark89e30]

I'd start with your ignition system. Since you already had the plugs out, how did they look, and did you re-gap them by chance? They could still be bad if they are cracked inside. Aside from that, measure your plug wire resistance. If none of that works, try swapping plugs and injectors with other cylinders and see if your dead holes move. And while you're in there, pull of that distributer cap. And after it gets really dark outside, watch your engine while its running and look for jumping sparks along the wires etc. Check ALL of the basics FIRST...

[BmwEvoSport]

thanks , the injectors look like a big job , dont i have to take the intake off to get to them?
Or can i just use a injector tester on them ?

[PУCCKAЯ_e30ka]

how did the sparkplugs look? you should be able to figure out what's wrong from that!

[BmwEvoSport]

I think i might have to just junk this motor and do a swap .

[fwappy]

Wait back up a sec... motor swap before removing injectors? What happened to sanity?

M20s are simple, man. Just get in there and get dirty!

[dark89e30]

You definitely CAN remove the injectors without removing the intake. Do NOT take the plenum off (unless you want to waste time). My advice if you have never done it before is to have some type of flexible magnet along with a good flashlight, a mirror on a stick and some goddamn patience and determination. Those injector clips can be a real bitch if they haven't come off in a few years and they will get lost. Just make sure you take the pcv hose out of the car. And if you can't do that, you can always do an engine swap...

[jlevie]

Before diving into the injectors, new plugs, ignition wires, rotor, and cap should be tried. If that doesn't fix the problem use a test light to see if there are firing pulses to those injectors. A lack of firing pulses indicates a bad DME. Otherwise you need a couple of new injectors.

[CorvallisBMW]

You can also use a plastic-handle screwdriver to listen for the 'click' noise the injectors make as they open/close. Way easier than pulling them and checking!

As far the the plug wires go, take them off and hold the boot up close to the engine and see if spark jumps. If it does, then try the same thing with the plugs removed, but still attached to the wires. Again, ground the plug on the engine and check to see if there is park jumping from the ground to the electrode. OR use a multimeter and check the resistance of each wire, that's probably easier.

As was stated above, check your distributor and rotor too.

[BmwEvoSport]

Thanks guys. ill let you know what happends.